Abstract
OTEX (Ocean Thermal Energy eXchange) is an open-source Python package for the design, simulation, and techno-economic assessment of Ocean Thermal Energy Conversion (OTEC) power plants. It implements three cycle architectures, closed Rankine (with simple, Kalina, and Uehara variants), open Rankine, and hybrid, realized as five configurations with pure and ammonia-water working fluids, coupled to heat-exchanger sizing, seawater hydraulics, and off-design operation. Integration with global ocean reanalysis data (CMEMS, HYCOM) enables site-specific resource assessment, while levelized cost of electricity and Monte Carlo and Sobol uncertainty analysis support comparative evaluation. A spatially resolved case study of Cuban waters demonstrates multi-configuration optimization of net power and cost.